The North Fork South Branch Potomac River flows past Seneca Rocks in Monongahela National Forest in Pendleton County, W.Va., on April 28, 2017. (Photo by Will Parson/Chesapeake Bay Program). (Download on Flickr)

The North Fork South Branch Potomac River flows past Seneca Rocks in Monongahela National Forest in Pendleton County, W.Va., on April 28, 2017. (Photo by Will Parson/Chesapeake Bay Program). (Download on Flickr)

The North Fork South Branch Potomac River flows past Seneca Rocks in Monongahela National Forest in Pendleton County, W.Va., on April 28, 2017. (Photo by Will Parson/Chesapeake Bay Program). (Download on Flickr)

The North Fork South Branch Potomac River flows past Seneca Rocks in Monongahela National Forest in Pendleton County, W.Va., on April 28, 2017. (Photo by Will Parson/Chesapeake Bay Program). (Download on Flickr)

The North Fork South Branch Potomac River flows past Seneca Rocks in Monongahela National Forest in Pendleton County, W.Va., on April 28, 2017. (Photo by Will Parson/Chesapeake Bay Program). (Download on Flickr)